About Me

Sunday, July 19, 2009

65 year old farmer was brought to the hospital by his wife at midnight. She says he is having severe headache since last 8 hours after he returned from work. He is sweating a lot and tears are falling from his eyes. He says he is feeling weak and tired and has vomited once. The vomitus just contains what he has eaten in the evening and there was no blood. On examination his skin is cool and wet. His BP is 124/82 mm Hg and Pulse is 64/min. He appears to be confused and answers only a few questions. During the interview, he was repeatedly spitting in the thrash bin in the ER. Systemic examination is non significant, except his pupils are smaller and few twitches can be seen in his limb muscles. He is diagnosed as insecticide toxicity and atropine is administered. What is the mechanism of action of the toxin?

A) Blocks Acetylcholine receptor at the post synaptic membraneB) Stimulates Acetylcholine receptor at the post synaptic membraneC) Blocks the enzymes that produce choline & Acetate in the synapseD) Blocks the reuptake of choline in the presynaptic membraneE) Block release of AcetylcholineF) Blocks the Ryanodine receptorsG) Blocks the enzyme that metabolizes Catecholamines after uptake in the presynapse

SCROLL DOWN AT THE BOTTOM OF THE PAGE FOR LIVE CHAT DISCUSSION or Visit http://chatroll.com/usmle-step-1NOTE: THIS BLOG IS UPDATED WITH NEW QUESTIONS DAILY BETWEEN 9 - 11 PM central time.(Not online for few days now, will get back soon)